resolv: Move ns_samename into its own file, and into libc

But only as an internal symbol, __libc_ns_samename.  The libresolv
ABI is preserved.  This is because the function is deprecated, and
it does not make sense to add new symbol versions for deprecated
functions.

Also reformat the implementation to GNU style.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>

include/arpa/nameser.h

@@ -68,7 +68,6 @@ libresolv_hidden_proto (ns_parserr)
 libresolv_hidden_proto (ns_sprintrr)
 libresolv_hidden_proto (ns_sprintrrf)
 libresolv_hidden_proto (ns_samedomain)
-libresolv_hidden_proto (ns_samename)
 libresolv_hidden_proto (ns_format_ttl)
 
 extern __typeof (ns_makecanon) __libc_ns_makecanon;
@@ -87,6 +86,8 @@ extern __typeof (ns_name_uncompress) __ns_name_uncompress;
 libc_hidden_proto (__ns_name_uncompress)
 extern __typeof (ns_name_unpack) __ns_name_unpack;
 libc_hidden_proto (__ns_name_unpack)
+extern __typeof (ns_samename) __libc_ns_samename;
+libc_hidden_proto (__libc_ns_samename)
 
 # endif /* !_ISOMAC */
 #endif

resolv/Makefile

@@ -43,6 +43,7 @@ routines := \
   ns_name_skip \
   ns_name_uncompress \
   ns_name_unpack \
+  ns_samename \
   nsap_addr \
   res-close \
   res-name-checking \

resolv/Versions

@@ -73,6 +73,7 @@ libc {
     __libc_dn_expand;
     __libc_dn_skipname;
     __libc_ns_makecanon;
+    __libc_ns_samename;
     __libc_res_dnok;
     __libc_res_hnok;
     __ns_name_compress;

resolv/ns_print.c

@@ -103,9 +103,9 @@ ns_sprintrrf(const u_char *msg, size_t msglen,
 	/*
 	 * Owner.
 	 */
-	if (name_ctx != NULL && ns_samename(name_ctx, name) == 1) {
+	if (name_ctx != NULL && __libc_ns_samename (name_ctx, name) == 1)
 		T(addstr("\t\t\t", 3, &buf, &buflen));
-	} else {
+	else {
 		len = prune_origin(name, origin);
 		if (*name == '\0') {
 			goto root;
@@ -621,7 +621,7 @@ prune_origin(const char *name, const char *origin) {
 	const char *oname = name;
 
 	while (*name != '\0') {
-		if (origin != NULL && ns_samename(name, origin) == 1)
+		if (origin != NULL && __libc_ns_samename (name, origin) == 1)
 			return (name - oname - (name > oname));
 		while (*name != '\0') {
 			if (*name == '\\') {

resolv/ns_samedomain.c

@@ -139,31 +139,9 @@ libresolv_hidden_def (ns_samedomain)
  *	is "a" a subdomain of "b"?
  */
 int
-ns_subdomain(const char *a, const char *b) {
-	return (ns_samename(a, b) != 1 && ns_samedomain(a, b));
+ns_subdomain (const char *a, const char *b)
+{
+  return __libc_ns_samename (a, b) != 1 && ns_samedomain (a, b);
 }
 
-/*%
- *	determine whether domain name "a" is the same as domain name "b"
- *
- * return:
- *\li	-1 on error
- *\li	0 if names differ
- *\li	1 if names are the same
- */
-
-int
-ns_samename(const char *a, const char *b) {
-	char ta[NS_MAXDNAME], tb[NS_MAXDNAME];
-
-	if (__libc_ns_makecanon(a, ta, sizeof ta) < 0 ||
-	    __libc_ns_makecanon(b, tb, sizeof tb) < 0)
-		return (-1);
-	if (strcasecmp(ta, tb) == 0)
-		return (1);
-	else
-		return (0);
-}
-libresolv_hidden_def (ns_samename)
-
 /*! \file */

resolv/ns_samename.c

@@ -0,0 +1,38 @@
+/* Check if two domain names are equal after trailing dot normalization.
+ * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
+ * Copyright (c) 1995,1999 by Internet Software Consortium.
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
+ * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
+ * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
+ * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
+ * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
+ * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
+ * SOFTWARE.
+ */
+
+#include <arpa/nameser.h>
+#include <string.h>
+
+/* Determines whether domain name A is the same as domain name B.
+   Returns -1 on error, 0 if names differ, 1 if names are the
+   same.  */
+int
+__libc_ns_samename (const char *a, const char *b)
+{
+  char ta[NS_MAXDNAME], tb[NS_MAXDNAME];
+
+  if (__libc_ns_makecanon (a, ta, sizeof ta) < 0 ||
+      __libc_ns_makecanon (b, tb, sizeof tb) < 0)
+    return -1;
+  if (__strcasecmp (ta, tb) == 0)
+    return 1;
+  else
+    return 0;
+}
+libc_hidden_def (__libc_ns_samename)

resolv/res_query.c

@@ -656,7 +656,7 @@ __res_context_hostalias (struct resolv_context *ctx,
 		if (!*cp1)
 			break;
 		*cp1 = '\0';
-		if (ns_samename(buf, name) == 1) {
+		if (__libc_ns_samename(buf, name) == 1) {
 			while (isspace(*++cp1))
 				;
 			if (!*cp1)

resolv/res_send.c

@@ -224,8 +224,8 @@ res_nameinquery(const char *name, int type, int class,
 			return (-1);
 		NS_GET16(ttype, cp);
 		NS_GET16(tclass, cp);
-		if (ttype == type && tclass == class &&
-		    ns_samename(tname, name) == 1)
+		if (ttype == type && tclass == class
+		    && __libc_ns_samename (tname, name) == 1)
 			return (1);
 	}
 	return (0);

resolv/resolv-deprecated.c

@@ -33,3 +33,9 @@ ns_makecanon (const char *src, char *dst, size_t dstsize)
 {
   return __libc_ns_makecanon (src, dst, dstsize);
 }
+
+int
+ns_samename (const char *a, const char *b)
+{
+  return __libc_ns_samename (a, b);
+}